78418138 has 4 divisors (see below), whose sum is σ = 117627210. Its totient is φ = 39209068.

The previous prime is 78418103. The next prime is 78418141. The reversal of 78418138 is 83181487.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83181487 = 19 ⋅4377973.

It can be written as a sum of positive squares in only one way, i.e., 73564929 + 4853209 = 8577^2 + 2203^2 .

It is a super-2 number, since 2×78418138² = 12298808734774088, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 78418138.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19604533 + ... + 19604536.

Almost surely, 2^78418138 is an apocalyptic number.

78418138 is a deficient number, since it is larger than the sum of its proper divisors (39209072).

78418138 is a wasteful number, since it uses less digits than its factorization.

78418138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39209071.

The product of its digits is 43008, while the sum is 40.

The square root of 78418138 is about 8855.4016283848. The cubic root of 78418138 is about 428.0279955193.

The spelling of 78418138 in words is "seventy-eight million, four hundred eighteen thousand, one hundred thirty-eight".